Studium mikrostruktury svorníků přírubových spojů pohonů HRK

Abstract

The thesis focuses on the study of the microstructure of flange joint bolts used in HRK drives of VVER-type nuclear reactors. The aim of the work is to analyze changes in the microstructure and mechanical properties of the bolts after long-term service. A comparison between an unused and a used bolt was carried out using electron microscopy, hardness measurements, and chemical analysis. The observed differences in microstructure and hardness, particularly in the threaded areas, were attributed to different manufacturing processes (machining vs. upsetting), and no significant operational degradation was identified. The thesis highlights the necessity for modernization of material technologies and regular inspection of components.